This will be my first project on an Arduino, so bear with me if I am asking questions that might have already been answered.

I have been researching the most fool-proof setup for controlling a powerful servo, and I think I have come up with the best solution.My means are limited in sense of funding, so investing in a motor board should be my last resort - e.g. if this does not work.

My setup will be: Arduino Uno (w/5V AC/DC) connected to a 5V 800mA(!) servo - which has its own power source (5V 1A - AC/DC).

Here is my question:

Would the following schematic provide fool-proof control of a 5V/800mA servo?- and if yes, how can it be optimized to perfection?

I have created this schematic based on how I de-ciphered comments around the web.

You show both the emitter and the collector leads of the transistor wired to ground. How could that possibly work? Why the transistor and diode in the first place? They serve no required purpose, even if wired correctly.

Any typical R/C servo wires the same for a arduino, arduino output pin control signal to servo control signal input pin, arduino ground pin to servo ground pin, servo ground pin to external power (4.8 to 6.0vdc) source, servo ground to external power source negative terminal.

This is not a high-current load though, despite it being a "powerful" servo it still has a logic-level input. Somewhere inside you would probably find some amplification but you shouldn't have to worry about it.